To support the new features of UL SU-MIMO, non-contiguous resource allocation (RA) and carrier aggregation (CA) in LTE-A Rel-10, UL transmission mode needs to be determined and the downlink control information format (DCI format) for UL grant needs to be designed, and control signaling overhead and blind decoding complexity is particularly involved therein.
In latest standardization meetings, in terms of the above three features, consensus is agreed as follows:
1. DL/UL transmission mode can be configured independently.
2. about non-contiguous RA                Frequency hopping is not supported simultaneously with non-contiguous PUSCH resource allocation;        Support dynamic switching between Rel-8 single cluster transmission and Rel-10 multi-cluster PUSCH transmission;        No additional blind decodings to support non-contiguous UL RA in single antenna transmission case        “No additional blind decodings to support non-contiguous UL RA” also applies to SU-MIMO case if SU-MIMO is supported with non-contiguous UL RA.        
3. About CA                CIF is not included in DCI format 0, 1 A in common search space when CRC is scrambled by C-RNTI/SPS C-RNTI;        Cross carrier scheduling for DCI format 0, 1, 1A, 1B, 1D, 2, 2A, 2B in UE specific search space should be supported by explicit CIF always, wherein DCI format 0 for UL grant, and other DCI format for indicating the DCI format of control information used when UE receiving downlink signal.        
4. about UL SU-MIMO                At least two new Rel-10 UE-specific RRC-configured transmission modes for PUSCH of UE with multiple Antenna Ports(AP):        Single-antenna port mode;                    Multi-antenna port mode supporting up to 2 Transport Block(TB), wherein, the number of antenna ports depends on the UE capability;            FFS whether or not a third RRC-configured multi-antenna transmission mode is needed.                        For PUSCH, a dynamic switching between the configured transmission scheme and a single-port fallback scheme with the same DCI format for all RRC configured modes;        2NDI and 2A/N are needed for up to 2TBs;        Reuse the CW (codeword)-to-layer mapping principle as in LTE Rel-8 DL spatial multiplexing;        For 2-Tx, 3-bit precoding codebook(CB) is specified, wherein:                    Size-6 CB for rank-1 precoding;            1 identity matrix for rank-2 (namely full-rank) precoding;                        For 4-Tx, 6-bit precoding codebook is specified, wherein:                    Size-24 CB for rank-1 precoding;                        
Size-16 CB for rank-2 precoding;                                    Size-12 CB for rank-3 precoding;            1 identity matrix for rank-4 (namely full-rank) precoding;                        Other related issues                    Dynamic aperiodic SRS is supported;                        
CS separation is the primary multiplexing scheme of DM RS;
OCC separation between slots may be used as complementary multiplexing scheme of DMRS, where the OCC index is implicitly derived.